Fossil echinoids

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Fossil of Acrocidaris, an extinct sea urchin Acrocidaris aff. nobilis - Canjuers.jpg
Fossil of Acrocidaris , an extinct sea urchin

Echinoid fossils are the fossilised remains of sea urchins, spiny marine invertebrates that live on the seabed. Humans have been interested in these fossils for millennia, have considered them lucky, have imbued them with magical powers and linked them to their deities. [1]

Contents

Echinoid fossils

The main feature of echinoid fossils are the set of five ambulacra on the test radiating out from a central point, forming a distinctive five-petalled pattern. [1] The earliest echinoid fossils date from the late Ordovician period, some 450 Mya. [2] The group has a rich fossil record, their hard tests made of calcite plates and their spines being found in rocks from every period since then. [3] Echinoids from the Paleozoic era had thin tests and their fossils are often incomplete, consisting of groups of plates or isolated spines. Later echinoids had more robust tests and fossilised well, usually with the spines detached from the test. [4] Fossils of echinoids are common in rocks from the Jurassic and Cretaceous age, especially from late Cretaceous chalk. In the White Cliffs of Dover in southern England, the echinoid fossils that are present can be used for dating the various chalk strata in which they occur. This is because they are relatively abundant and well-preserved compared to other fossilised animals, and can be differentiated by type between different ages. [1]

Use in culture

A fossil sea urchin found on a Middle Saxon site in Lincolnshire, thought to have been used as an amulet. Fossil sea urchin (FindID 551527).jpg
A fossil sea urchin found on a Middle Saxon site in Lincolnshire, thought to have been used as an amulet.

Humans have long had a propensity for collecting fossil echinoids, and these fossils are often found at archaeological sites. The fossils played a part in both Celtic and Norse mythology, were venerated, associated with burials, woven into myths and legends and used when making tools and decorative objects. [6] These fossils are commonly known as thunderstones, fairy loaves, or shepherds' crowns. [1]

Echinoid fossils are sometimes found associated with archaeological sites. The earliest known example in England is an Acheulean hand axe from the Middle Pleistocene found in Kent. The craftsman had evidently chosen to use this flint for his tool; the exposed area around the sea urchin's jaws known as Aristotle's lantern are clearly visible. Similar examples are known from France, Western and Central Europe, and Northern Africa; they span Paleolithic, Neolithic, Bronze Age, and Iron Age times. [6]

Related Research Articles

The Cretaceous is a geological period that lasted from about 145 to 66 million years ago (mya). It is the third and final period of the Mesozoic Era, as well as the longest. At nearly 80 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, 'chalk', which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation Kreide.

Fossil Preserved remains or traces of organisms from a past geological age

A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.

Sea urchin Class of echinoderms

Sea urchins, are typically spiny, globular animals, echinoderms in the class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal to 5,000 metres. Their hard shells (tests) are round and spiny, usually from 3 to 10 cm across. Sea urchins move slowly, crawling with their tube feet, and sometimes pushing themselves with their spines. They feed primarily on algae but also eat slow-moving or sessile animals. Their predators include sea otters, starfish, wolf eels, triggerfish, and humans.

Chert A hard, fine-grained sedimentary rock composed of cryptocrystalline silica

Chert is a hard, fine-grained sedimentary rock composed of microcrystalline (or cryptocrystalline) crystals of quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin but may also occur inorganically as a chemical precipitate or a diagenetic replacement, as in petrified wood.

Gideon Mantell British scientist and obstetrician

Gideon Algernon Mantell MRCS FRS was an English obstetrician, geologist and palaeontologist. His attempts to reconstruct the structure and life of Iguanodon began the scientific study of dinosaurs: in 1822 he was responsible for the discovery of the first fossil teeth, and later much of the skeleton, of Iguanodon. Mantell's work on the Cretaceous of southern England was also important.

Chalk Group

The Chalk Group is the lithostratigraphic unit which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur across the wider northwest European chalk 'province'. It is characterised by thick deposits of chalk, a soft porous white limestone, deposited in a marine environment.

Geology of Dorset

Dorset is a county in South West England on the English Channel coast. Covering an area of 2,653 square kilometres (1,024 sq mi); it borders Devon to the west, Somerset to the north-west, Wiltshire to the north-east, and Hampshire to the east. The great variation in its landscape owes much to the underlying geology which includes an almost unbroken sequence of rocks from 200 Ma to 40 Ma and superficial deposits from 2 Ma to the present. In general the oldest rocks appear in the far west of the county, with the most recent (Eocene) in the far east. Jurassic rocks also underlie the Blackmore Vale and comprise much of the coastal cliff in the west and south of the county; and although younger Cretaceous rocks crown some of the highpoints in the west, they are mainly to be found in the centre and east of the county.

A thunderstone is a Prehistoric hand axe, stone tool, or fossil which was used as an amulet to protect a person or a building. The name derives from the ancient understanding that the object was found at a place where lightning had struck.

<i>Echinothrix diadema</i> Species of sea urchin

The diadema urchin or blue-black urchin is a species of tropical sea urchin, member of the Diadematidae family.

<i>Micraster</i> Extinct genus of sea urchins

Micraster is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it.

<i>Colobocentrotus atratus</i> Species of sea urchin

Colobocentrotus atratus, the helmet urchin or shingle urchin, is a species of sea urchin in the family Echinometridae. In Hawaii it is known as "kaupali" which translates as "cliff-clinging". It is found on wave-swept intertidal shores in the Indo-West Pacific, particularly on the shores of Hawaii.

Echinacea (animal) Superorder of sea urchins

The Echinacea are a superorder of sea urchins. They are distinguished by the presence of a rigid test, with ten buccal plates around the mouth, and solid spines. Unlike some other sea urchins, they also possess gills. The group is a large one, with species found worldwide.

Echinothurioida Order of sea urchins

The Echinothurioida are an order of sea urchins in the class Echinoidea. Echinothurioids are distinguished from other sea urchins by the combination of a flexible test and hollow spines. The membrane around the mouth contains only simple plates, in contrast to the more complex mouth parts of their close relatives, the Diadematoida. They are nearly all deepsea dwellers.

Geology of East Sussex Overview of the geology of East Sussex

The geology of East Sussex is defined by the Weald–Artois anticline, a 60 kilometres (37 mi) wide and 100 kilometres (62 mi) long fold within which caused the arching up of the chalk into a broad dome within the middle Miocene, which has subsequently been eroded to reveal a lower Cretaceous to Upper Jurassic stratigraphy. East Sussex is best known geologically for the identification of the first dinosaur by Gideon Mantell, near Cuckfield, to the famous hoax of the Piltdown man near Uckfield.

Psychocidaridae Family of echinoderms

Psychocidaridae is a family of sea urchins in the order Cidaroida. The genus Psychocidaris is extant while the other genera are only known from fossils. The family has been in existence since the Lower Jurassic (Toarcian) and the range includes Europe, Ukraine, North America, North Africa and the West Pacific.

Paleontology in Alabama

Paleontology in Alabama refers to paleontological research occurring within or conducted by people from the U.S. state of Alabama. Pennsylvanian plant fossils are common, especially around coal mines. During the early Paleozoic, Alabama was at least partially covered by a sea that would end up being home to creatures including brachiopods, bryozoans, corals, and graptolites. During the Devonian the local seas deepened and local wildlife became scarce due to their decreasing oxygen levels.

Paleontology in Texas

Paleontology in Texas refers to paleontological research occurring within or conducted by people from the U.S. state of Texas. Author Marian Murray has remarked that "Texas is as big for fossils as it is for everything else." Some of the most important fossil finds in United States history have come from Texas. Fossils can be found throughout most of the state. The fossil record of Texas spans almost the entire geologic column from Precambrian to Pleistocene. Shark teeth are probably the state's most common fossil. During the early Paleozoic era Texas was covered by a sea that would later be home to creatures like brachiopods, cephalopods, graptolites, and trilobites. Little is known about the state's Devonian and early Carboniferous life. However, evidence indicates that during the late Carboniferous the state was home to marine life, land plants and early reptiles. During the Permian, the seas largely shrank away, but nevertheless coral reefs formed in the state. The rest of Texas was a coastal plain inhabited by early relatives of mammals like Dimetrodon and Edaphosaurus. During the Triassic, a great river system formed in the state that was inhabited by crocodile-like phytosaurs. Little is known about Jurassic Texas, but there are fossil aquatic invertebrates of this age like ammonites in the state. During the Early Cretaceous local large sauropods and theropods left a great abundance of footprints. Later in the Cretaceous, the state was covered by the Western Interior Seaway and home to creatures like mosasaurs, plesiosaurs, and few icthyosaurs. Early Cenozoic Texas still contained areas covered in seawater where invertebrates and sharks lived. On land the state would come to be home to creatures like glyptodonts, mammoths, mastodons, saber-toothed cats, giant ground sloths, titanotheres, uintatheres, and dire wolves. Archaeological evidence suggests that local Native Americans knew about local fossils. Formally trained scientists were already investigating the state's fossils by the late 1800s. In 1938, a major dinosaur footprint find occurred near Glen Rose. Pleurocoelus was the Texas state dinosaur from 1997 to 2009, when it was replaced by Paluxysaurus jonesi after the Texan fossils once referred to the former species were reclassified to a new genus.

Calveriosoma gracile is a species of sea urchin in the order Echinothurioida. It is a deep water species and is found on the seabed in western parts of the Pacific Ocean at depths of 200 to 800 metres.

Pelanechinus is an extinct genus of sea urchins in the order Echinothurioida. It is placed in the family Pelanechinidae and is in the stem group of echinoids.

Echinothuriidae Family of sea urchins

The Echinothuriidae are a family of sea urchins in the order Echinothurioida. Due to their soft skeletons, most are called "leather urchins", but species in the genus Asthenosoma are also known as "fire urchins" due to their bright colors and painful, venomous sting.

References

  1. 1 2 3 4 "Echinoids". BGS fossils and geological time. British Geological Survey. Retrieved 5 March 2021.
  2. "Echinoids". British Geological Survey. 2017. Retrieved 6 March 2021.
  3. "The Echinoid Directory: Introduction". Natural History Museum. Retrieved 6 March 2021.
  4. Kirkaldy, J. F. (1967). Fossils in Colour. Blandford Press. pp. 161–163.
  5. "Amulet | LIN-B37563". Portable Antiquities Scheme. Retrieved 7 March 2021.
  6. 1 2 McNamara, Kenneth J. (2007). "Shepherds' crowns, fairy loaves and thunderstones: the mythology of fossil echinoids in England". Geological Society, London, Special Publications. 273 (1): 279–294. Bibcode:2007GSLSP.273..279M. CiteSeerX   10.1.1.868.346 . doi:10.1144/GSL.SP.2007.273.01.22. S2CID   129384807.